1. Field of the Invention
The present invention relates to an electronic musical instrument that generates a musical tone according to a musical tone signal generated based on an operated state of an operating element for musical performance.
2. Description of the Related Art
As a conventional loudspeaker unit that generates a musical tone according to an electric signal, there has been known one disclosed e.g. in Japanese Laid-Open Patent Publication (Kokai) No. H11-32388. This loudspeaker unit is comprised of a cabinet, a loudspeaker, and a vibration exciter. The loudspeaker is mounted on a baffle board covering the front of the cabinet, and the vibration exciter is mounted on a backboard covering the rear of the cabinet. The loudspeaker receives an audio signal from an audio amplifier, and sound is generated from the loudspeaker according to the audio signal. The same audio signal as received by the loudspeaker is input to the vibration exciter as well, and the vibration exciter vibrates the cabinet according to the audio signal so as to cancel vibration of the cabinet caused by the generation of the sound from the loudspeaker. Thus, the conventional loudspeaker unit prevents movement of the cabinet due to vibration of the cabinet caused by the generation of sound from the loudspeaker.
Further, in recent years, there has been known an electronic musical instrument, such as an electronic keyboard instrument, which generates a musical tone according to a musical tone signal generated based on a depressed state of a key. When the above-described conventional loudspeaker unit is applied to an electronic musical instrument of this type, the following inconvenience occurs: Since the vibration exciter is configured to excite the cabinet not to generate a musical tone, but to cancel vibration of the cabinet caused by the generation of sound from the loudspeaker, as described above, a musical tone is output exclusively from the loudspeaker disposed in the front of the cabinet. Therefore, the electronic musical instrument equipped with the conventional loudspeaker unit is not capable of providing spatially spread musical tones characterizing an electronic musical instrument.
Further, in the conventional loudspeaker unit, the loudspeaker and the vibration exciter are simply attached to the cabinet independently of each other, so that the sound pressure of a musical tone generated by the electronic musical instrument cannot be increased sufficiently, and therefore it is impossible to obtain dynamic musical tones characterizing an electronic musical instrument.